1. Field of the Invention
The present invention relates to homokinetic joints which may be used in particular in lateral transmissions of front-wheel drive vehicles, or vehicles which are propelled through independent wheels, and in longitudinal transmissions conventionally equipped with universal joints.
2. Description of the Prior Art
There is known from the patent FR-A-81 10 796, corresponding to U.S. Pat. No. 4,490,126, a telescopic homokinetic joint comprising a first element having three pairs of planes evenly spaced angularly apart around a first axis, the planes of each pair being parallel to each other and to this first axis, a second element defining three spherical bearing surfaces which are evenly angularly spaced apart around a second axis, and intermediate elements comprising, on one hand, planar surfaces, respectively parallel to said planes and, on the other hand, spherical surfaces cooperating with said spherical bearing surfaces, rolling elements, in the present instance needles, being interposed between the planar surfaces of the intermediate elements and the planes of the first element.
Such a joint affords a considerable improvement in the comfort of the vehicle in which it is installed by its very free sliding under torque for small angularities (less than 5.degree.), and by a complete neutrality in axial translation and in bending moment when it operates under a medium angularity, for example between 8.degree. and 6.degree..
However, in applications in which the transmission rotates at high speed (for example exceeding 4,000 rpm), this technique which performs well at moderate speed is no longer fully satisfactory.